Portable sand blast apparatus



Oct. 2, 1962 R. A. MCMILLIN 3,056,236

PORTABLE SAND BLAST APPARATUS Filed Oct. 12, 1961 2 Sheets-Sheet 1 I 1 l I I l l l I l Oct. 2, 1962 R. A. MCMILLIN 3,056,236

I PORTABLE SAND BLAST APPARATUS Filed 001;. 12. 1961 2 Sheets-Sheet 2 P 3,056,236 PGRTABLE SAND BLAST APPARATUS Roy A. McMillin, -14 Pd). Box 7 83, Page, Ariz. Filed Get. 12, 1961, Ser. No. 144,630 Claims. (Cl. 51-8) This invention relates to abrading, and more particularly to a portable sand blast apparatus which may be conveniently utilized in any desired location and in which the entire operation may be conveniently controlled from the blasting position and without requiring any attention at the location of the sand feeding hopper other than keeping an adequate supply of sand in such hopper, the entire operation thereof, as stated above, being controlled from the blasting location.

Many different types of sand blasting apparatus, including hopper feeding means for sand and blasting nozzles have heretofore been proposed and utilized, but many such prior art units are relatively heavy and cumbersome and frequently require a relatively firm foundation for proper operation and also requiring the use of excessive lengths of hose for supplying sand and air to the blasting nozzle. Furthermore, many of these prior art units required that an attendant be present at the location of the sand feeding hopper in order to control operation of the same for initiating and stopping the feeding of sand or required that the blasting nozzle operator travel to and from the location of the sand hopper when ceasing or starting blasting operations. It has also been found that in many cases sand becomes bridged or clogged at the outlet of the sand hopper necessitating considerable manual labor in order to clear the same and re-establish flow of the sand from the hopper.

It is accordingly an object of the invention to provide a portable sand blast apparatus which is relatively small and light in weight thereby permitting convenient transportation and use in any desired location.

A further object of the invention is the provision of a portable sand blast apparatus in which the hopper and associated mechanism for containing and feeding sand may be positioned on the ground in any desired location or may be suspended from a ladder or scaffold in order to provide for convenient blasting operations in relatively inaccessible locations.

A still further object of the invention is the provision of a portable sand blast apparatus, including a hopper for containing and feeding sand and in which the rate of feed of such sand may be conveniently controlled by a relatively simple, manually operable throw control mechanism.

Another object of the invention is the provision of a portable sand blast apparatus, including a hopper for containing and feeding sand and in which a shut-off valve is provided on the hopper for permitting or stopping flow of sand therefrom, such shut-ofl valve being pneumatically operated and completely controlled from the blasting position.

A further object of the invention is the provision of a portable sand blast apparatus in which a single valve for controlling the flow of air to the blasting nozzle also operates to control the opening or closing of a shut-off valve on the sand feeding hopper for initiating or stopping the flow of sand therefrom.

A still further object of the invention is the provision of a portable sand blast apparatus, including a blasting nozzle having a removable air jet therein which may be replaced by jets of different sizes and in which the blasting gun or nozzle provides for maximum vacuum to facilitate the flow of sand thereto.

Another object of the invention is the provision of a portable sand blast apparatus, including a hopper for containing and feeding sand and in which a tube is proaent vided within the hopper for directing a blast of air into the sand discharge opening to dislodge sand which has clogged such opening, thereby serving to re-establish flow therethrough, the operation of this sand clearing mechanism being accomplished by a supply of air provided from the blasting nozzle and controlled by a valve located adjacent such nozzle, thereby permitting complete control of the apparatus by the nozzle operator.

A further object of the invention is the provision of a portable sand blast apparatus which may be conveniently and economically constructed from readily available materials and which may be utilized to perform any desired sand blasting operation, the apparatus being so designed as to require only a single operator manipulating the blasting nozzle and completely controlling operation of the apparatus from this location.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is an elevational and diagrammatic view with parts broken away and in section for greater clarity and showing the details of structure of the entire apparatus, together with the various fluid pressure connections between the sand containing and feeding hopper and the blasting nozzle;

FIG. 2 a bottom plan view of the hopper showing the means for controlling the rate of flow of sand therefrom, as well as a portion of the shut-off valve structure;

FIG. 3 an elevational view with parts broken away and in section for greater clarity and showing the structure of the blasting nozzle, as well as the air supply control valve and the connection of the sand supply conduit and the connection of conduits to a bleed fitting for controlling operation of the sand shut-off valve, as well as the operation of the means for maintaining flow of sand through the discharge opening of the hopper;

FIG. 4 a plan view of a plate secured to the bottom wall of the hopper and containing a discharge opening, which plate cooperates with a valve plate for controlling the rate of flow of sand discharged from the hopper; and

FIG. 5 a plan View of the sand flow control plate which may be adjusted for the desired rate of flow of sand from the hopper.

With continued reference to the drawing, there is shown a portable sand blast apparatus constructed in accordance with this invention and which may well include a hopper 10 for receiving and feeding sand and such hopper may be constructed of suitable light weight sheet material and may be provided with frame members 11 affording adequate support for the hopper and if desired, such frame members 11 may support the hopper 10 on a suitable wheeled vehicle or means may be provided for merely supporting the hopper on the ground' or for suspending the same from a ladder or scaffold. The hopper 10 may have an open top for facilitating filling the same with sand or may be provided with suitable closure means, such as a screen to permit the free flow of air, but preventing entry of foreign objects.

Certain of the sidewalls of the hopper 10 converge inwardly at the lower portion thereof and are attached to a bottom wall 12 to provide a sand feeding sump 13.

opening 16 in alignment with the opening 14 in the bottom wall 12. A sand flow control plate 17 is rotatably mounted below the plate 15 and in contact with the lower surface thereof by screw threaded or other suitable.

means 18 and the flow control plate 17 is provided with an aperture 19 which may be moved into and out of alignment with the apertures 14 and 16 upon rotation of the plate 17. As shown in FIGS. 2 and 5, the flow control plate 17 may be provided with a finger engaging projection 20 for convenient operation thereof and a plurality of notches 21 may be provided in the edge of the flow control plate 17, which notches serve to selectively receive the plunger 22 of a detent mechanism 23 incorporating a compression spring 24 for urging the plunger or ball 22 into the notches 21. The detent mechanism 23 may be secured to the bottom wall 12 of the hopper 10. As will be seen, rotation of the flow control plate 17 will operate to vary the cross sectional size of the discharge openings 14, 16 and 19 to control the rate of flow of sand from the hopper 10.

A tubular housing 25 is secured to the bottom wall 12 of the hopper 10 by welding or other suitable means .and also, if desired, by means of a suitable bracket 26 and the housing 25 is provided with a sand receiving portion 27 communicating with the sand discharge openings 14, 1'6 and 19. One end 28 of the housing 25 is connected to a flexible conduit 29 and the opposite end 30 of the housing 25 is open to permit flow of air into the housing 25 and also .for another purpose which will presently appear.

A suitable bracket 31 is mounted on the sidewall 32 of'the hopper 16 and pivotally mounted on the bracket 31 at 33 is one end of an elongated plate 34, the opposite end 35 of the plate 34 projecting into the housing 25 through the open end 30 to a position directly below the sand discharge openings 14, 16 and 19. The plate 34 provides a sand shut-off valve which is normally urged upwardly by a tension spring 36 to the position shown in FIG. 1 which serves to prevent flow of sand from the hopper 10 through the openings 14, 16 and 19 into the sand receiving portion 27 of the housing 25. A shut-off valve operating actuating mechanism in the form of a cylinder 37 is pivotally mounted at 38 on the bracket 31 and a piston 39 slidably mounted in the cylinder 37 is provided with a piston rod 46 pivotally connected at 41 to the plate 34 forming the shut-off valve and obviously, operation of the piston 39 and piston rod downwardly will also move the plate 34 downwardly to permit flow of sand from the hopper 10 into the portion 27 of the housing 25. A return spring 42 may be provided in the cylinder 37 for returning the piston 33 and piston rod 40 upwardly after operation thereof and in accordance with closing movement of the shut-off valve plate 34. The upper end of the cylinder 37 may be connected to .a flexible conduit 43.

A tube 44 is mounted on the inner surface of the sidewall 32 of the hopper 10 by a suitable bracket 45 and the tube 44 extends downwardly with the open end 46 thereof terminating in alignment and above the discharge opening 14 in the bottom wall 12 of the hopper 16 and the upper end of the tube 44 may be connected to a flexible conduit 47 for .a purpose to be later described.

With particular reference to FIG. 3, there is shown a blasting nozzle which may well comprise a hollow fitting 48 having an axial passage 49 therein and a nozzle tip 50 of hard metal or other suitable material is removably secured as by screw threads 51 or the like, to the forward end of the fitting 48 in alignment with the axial passage 49. An air jet 52 is removably secured in the rear end of the fitting 4S and terminates substantially midway between the forward end 53 and the rear end 54 of the fitting 48, the jet 52 also being in alignment with the axial passage 49. A sand supply passage 55 is provided in the fitting 48 at an angle to the axial passage 49 and as shown in FIG. 3, the fitting 48 is substantially in the shape of a Y and the sand supply passage 55 is connected to the flexible conduit 29 which in turn is connected to the end 28 of the housing 25 on the hopper 10. It will be noted, that the sand supply passage 55 opens into the axial passage 49 forwardly and rearwardly of the forward end of the jet 52 and by reason of this arrangement, air flowing through the jet 52 into the axial passage 49 4 and out through the blasting tip 50 will result in creating a vacuum in the sand supply passage 55 and as a result thereof air will flow into the open end 36 of the housing 25 to convey sand therefrom through the flexible conduit 29 to the sand supply passage 55 and outwardly through the blasting tip 54).

An air supply control valve 56 is connected to the rear end 54 of the fitting 48, the valve 56 being connected to an air supply conduit 57 which in turn is connected to a suitable source of air under pressure and the valve 56 is provided with a suitable hand engaging control handle 58 to permit convenient opening and closing of the valve 56 by the nozzle operator. The outlet of the valve 56, of course, communicates with the jet 52, and operation of the valve control handle 58 will result in air flowing through the jet 52 or upon closing of the valve 56, flow of air will cease. A bleeder fitting 59 is provided on the valve 56 between the valve mechanism and the jet 52 and the bleeder fitting 59 is provided with a Y outlet 66, one arm of which is connected to the flexible conduit 43 which in turn is connected to the cylinder 37. The other arm of the Y '68 is connected to a flexible conduit 61 which in turn is connected to a valve 62 having a push button actuating means 63, the valve 62 in turn being connected to the flexible conduit 47 which is connected to the tube 44 in the hopper 16. Obviously, with the valve 56 open to establish flow of air from the supply conduit 57 to the jet 52, air will also be introduced into the conduits 43 and 61 connected to the bleeder fitting 49 and the purpose and operation of this arrangement will now be described.

In operation, it is assumed that a suflicient quantity of sand is present in the hopper 10 and that air supply conduit 57 is connected to a suitable source of air under pressure. When it is desired to start blasting operations, the handle 58 of the valve 56 is actuated to permit flow of air through the jet 52 into the fitting 48 out through the blasting tip 50. This will also cause a flow of air through the conduit 43 to the cylinder 37 which will result in moving the piston 39 and connecting rod 40 downwardly to move the plate 34 of the shut-off valve downwardly and permit flow of sand from the hopper 10 through the discharge openings 14, 16 and 19 into the sand receiving portion 27 of the housing 25. As stated above, flow of air from the jet 52 through the fitting 48 will result in providing a vacuum in the sand supply passage 55 and consequently, flow of air into the open end 30 of the housing 25 will operate to convey sand therefrom through the flexible conduit 29 to the fitting 43 and outwardly through the blasting tip 50. During the blasting operation, if for any reason sand should become clogged in the discharge opening from the housing 10, it is only necessary to actuate the pushbutton 63 of the valve 62 which will result in a blast of air from the open end 46 of the tube 44 which will serve to clear the sand from the discharge openings and re-establish flow therethrough. When it is desired to cease blasting operations, it is only necessary to actuate the handle 58 to close the valve 56 and stop the flow of air through the jet 52, at which time, flow of air to the cylinder 37 will also be stopped thereby permitting upward movement of the shut-off plate 34 under the action of springs 36 and 42 which will operate to interrupt the flow of sand to the housing 25. This operation may be repeated as often as desired without in any way necessitating travel of the nozzle operator from the nozzle location to the location of the hopper and in this manner, blasting operations may be performed continuously or intermittently until the supply of sand in the hopper 10 is exhausted, at which time the same may be replenished. While the blasting nozzle shown is primarily intended for dry blasting operations, if desired, wet blasting may be accomplished by substituting a suitable conventional wet blasting nozzle tip for the nozzle 50 shown in FIG. 3. The flow control plate 17 is, of course,

adjusted to provide the desired rate of flow of sand for the particular blasting operation being performed.

It will thus be seen that by the above described invention there has been provided a relatively simple, yet highly effective and convenient portable sand blast apparatus which may be completely controlled from the nozzle location and which may be conveniently moved and set up in any desired location. It is contemplated that the appa ratus will be constructed of suitable light weight materials thereby further facilitating transportation and use of the equipment.

It will be obvious to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawing and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. A portable sand blast apparatus comprising a hopper for containing a supply of sand, a discharge opening in the bottom wall of said hopper, a tubular housing open at opposite ends secured to said hopper below said discharge opening and communicating therewith, a bracket mounted on said hopper, a shut-ofl valve for said dis charge opening comprising an elongated plate pivotally mounted at one end on said bracket with the opposite end disposed in one end of said housing below said discharge opening, spring means for pivotally moving said plate upwardly to close said discharge opening, a cylinder pivotally mounted on said bracket above said plate, a piston in said cylinder having a piston rod pivotally connected to said plate to move the same downwardly upon operation of said piston to permit flow of sand through said discharge opening into said housing, a blasting nozzle comprising a hollow fitting having an axial passage, a nozzle tip removably secured to the forward end of said fitting in alignment with said passage, an air jet disposed in said passage at the rear end of said fitting and terminating in spaced relation to the inner end of said tip, a sand supply passage in said fitting disposed at an angle to said axial passage, said supply passage opening into said axial passage forwardly and rearwardly of the open end of said air jet, a flexible conduit connecting said supply passage and the opposite end of said housing, an air supply control valve connected to the rear end of said fitting and communicating with said jet, a flexible conduit connecting said air control valve and a source of air under pressure, a bleeder fitting between said air control valve and said jet and a flexible conduit connecting said bleeder fitting and said cylinder, where-by opening said air control valve air will flow through said jet, said axial passage and said nozzle tip to induce a vacuum in said supply passage and air will flow through said bleeder fitting to said cylinder to open said shut-off valve and permit sand to flow into said housing and through the conduit to said blast nozzle, the flow of sand being stopped by closing said air control valve and the resulting closing of said shut-oft valve.

2. A portable sand blast apparatus as defined in claim 1 in which a sand flow control plate is rotatably mounted on the bottom wall of said hopper, said control plate having an aperture movable into and out of alignment with said discharge opening to control the flow of sand therethrough, spaced notches in the edge of said control plate and a spring pressed detent mounted on said hopper and selectively received in one of said notches to releasably retain said control plate in adjusted position.

3. A portable sand blast apparatus as defined in claim 1 in which a sand flow control plate is rotatably mounted on the bottom wall of said hopper, said control plate having an aperture movable into and out of alignment with said discharge opening to control the flow of sand therethrough and means to releasably retain said control plate in adjusted position.

4. A portable sand blast apparatus as defined in claim 1 inwhich a tube is disposed in said hopper with an open end of said tube directed downwardly and terminating above said discharge opening in alignment therewith, said tube being connected through a flexible conduit with said bleeder fitting and a valve in said last named conduit whereby upon actuation of said last named valve a blast of air will be delivered from said tube to blow clogged sand from said discharge opening and reestablish the flow of sand therethrough.

5. A portable sand blast apparatus as defined in claim 1 in which a tube is disposed in said hopper with an open end of said tube directed downwardly and terminating above said discharge opening in substantial alignment therewith, said tube being connected through a flexible conduit with said bleeder fitting and means to control the flow of air through said last named conduit to deliver a blast of air to blow clogged sand from said discharge opening and reestablish the flow of sand therethrough.

6. A portable sand blast apparatus as defined in claim 1 in which said jet is removably secured in said hollow fitting, whereby jets of different size may be selectively installed.

7. A portable sand blast apparatus comprising a hopper for containing a supply of sand, a discharge opening in the bottom wall of said hopper, a tubular housing open at opposite ends secured to said hopper below said discharge opening and communicating therewith, a shutoff valve for said discharge opening comprising an elongated plate pivotally mounted at one end on said hopper with the opposite end disposed in one end of said housing below said discharge opening, means for pivotally moving said plate upwardly to close said discharge opening, a cylinder pivotally mounted on said hopper above said plate, a piston in said cylinder having a piston rod pivotally connected to said plate to move the same downwardly upon operation of said piston to permit flow of sand through said discharge opening into said housing, a blasting nozzle comprising a hollow fitting having an axial passage, a nozzle tip removably secured to the forward end of said fitting in alignment with said passage, an air jet disposed in said pasasge at the rear end of said fitting and terminating in spaced relation to the inner end of said tip, a sand supply passage in said fitting disposed at an angle to said axial passage, said supply passage opening into said axial passage forwardly and rearwardly of the open end of said air jet, a flexible conduit connecting said supply passage and the opposite end of said housing, an air supply control valve connected to the rear end of said fitting and communicating with said jet, a flexible conduit connecting said air control valve and a source of air under pressure, a bleeder fitting between said air control valve and said jet and a flexible conduit connecting said bleeder fitting and said cylinder, whereby upon opening said air control valve air will flow through said jet, said axial passage and said nozzle tip to induce a vacuum in said supply passage and air will flow through said bleeder fitting to said cylinder to open said shut-off valve and permit sand to flow into said housing and through the conduit to said blast nozzle, the flow of sand being stopped by closing said air control valve and the resulting closing of said shut-otf valve.

8. A portable sand blast apparatus comprising a hopper for containing a supply of sand, a discharge opening in the bottom wall of said hopper, a tubular housing open at opposite ends secured to said hopper below said discharge opening and communicating therewith, a shutofl valve for said discharge opening comprising an elongated plate pivotally mounted at one end of said hopper with the opposite end disposed in one end of said housing below said discharge opening, means for pivotally moving said plate upwardly to close said discharge open ing, a cylinder mounted on said hopper, a piston in said cylinder having a piston rod connected to said plate to move the same downwardly upon operation of said piston to permit the flow of sand through said discharge opening into said housing, a blasting nozzle comprising a hollow fitting having an axial passage, a nozzle tip removably secured to the forward end of said fitting in alignment with said passage, an air jet disposed in said passage at the rear end of said fitting and terminating in spaced relation to the inner end of said tip, a sand supply passage in said fitting disposed at an angle to said axial passage, said supply passage opening into said axial passage forwardly and rearwardly of the open end of said air jet, a flexible conduit connecting said supply passage and the opposite end of said housing, an air supply control valve connected to the rear end of said fitting and communicating with said jet, a flexible conduit connecting said air control valve and a source of air under pressure, a bleeder fitting between said air control valve and said jet and a flexible conduit connecting said bleeder fitting and said cylinder, whereby upon opening said air control valve air will flow through said jet, said axial passage and said nozzle tip to induce a vacuum in said supply passage and air will flow through said bleeder fitting to said cylinder to open said shut-off valve and permit sand to flow into said housing and through the conduit to said blast nozzle, the flow of sand being stopped by closing said air control valve and the resulting closing of said shut-off valve.

9. A portable sand blast apparatus comprising a hopper for containing a supply of sand, a discharge opening in the bottom wall of said hopper, a tubular housing open at opposite ends secured to said hopper below said discharge opening and communicating therewith, a shutoff valve for said discharge opening comprising an elongated plate pivotally mounted at one end on said hopper with the opposite ends disposed in one end of said housing below said discharge opening, means for pivotally moving said plate upwardly to close said discharge opening, a cylinder mounted on said hopper, a piston in said cylinder having a piston rod connected to said plate to move the same downwardly upon operation of said piston to permit flow of sand through said discharge opening into said housing, a blasting'nozzle comprising a hollow fitting having an axial passage, a nozzle tip at the forward end of said fitting in alignment with said passage, an air jet disposed in said passage at the rear end of said fitting and terminating in spaced relation to the inner end of said tip, a sand supply passage in said fitting, said supply passage opening into said axial passage, a flexible conduit connecting'said supply passage and the opposite end of said housing, an air supply control valve connected to the rear end of said fitting and communicating with said jet, a flexible conduit connecting said air control valve and the source of air under pressure, a bleeder fitting between said air control valve and said jet and a flexible conduit connecting said bleeder fitting and said cylinder, wherebyupon opening said air control valve air will flow through said jet, said axial passage and said nozzle tip toinduce a vacuum in said supply passage and air will flow through said bleeder fitting to said cylinder to open said shut-oif valve and permit sand to flow into said housing and through the conduit to said blast nozzle, the flow of sand being stopped by closing said air control valve and the resulting closing of said shut-off valve.

10. A portable sand blast apparatus comprising a hop per for containing a supply of sand, a discharge opening in the bottom wall of said hopper, a tubular housing open at opposite ends secured to said hopper below said discharge opening and communicating therewith, a shutofl valve for said discharge opening comprising an elongated plate disposed in one end of said housing below said discharge opening, means for moving said plate upwardly to close said discharge opening, a cylinder mounted on said hopper, a piston in said cylinder having a piston rod connected to said plate to move the same downwardly upon operation of said piston to permit flow of sand through said discharge opening into said housing, a blasting nozzle comprising a hollow fitting having an axial passage, a nozzle tip at the forward end of said fitting in alignment with said passage, an air jet disposed in said passage at the rear end of said fitting, a sand supply passage in said fitting, said supply passage opening into said axial passage, a flexible conduit connecting said supply passage and the opposite end of said housing, an air supply control valve connected to the rear end of said fitting and communicating with said jet, a flexible conduit connecting said air control valve and a source of air under pressure, a bleeder fitting between said air control valve and said jet and a flexible conduit connecting said bleeder fitting and said cylinder, whereby upon opening said air control valve air will flow through said jet, said air supply passage and said nozzle tip to induce a vacuum in said supply passage and air will flow through said bleeder fitting to said cylinder to open said shut-01f valve and permit sand to flow into said housing and'through the conduit to said blast nozzle, the flow of sand being stopped by closing said air control valve and the resulting closing of said shut-off valve.

References Cited in the file of this patent UNITED STATES PATENTS 1,443,762 Smith Jan. 30, 1923 1,535,939 Moore Apr. 28, 1925 1,585,549 Jorgensen May 18, 1926 1,858,475 Wolever May 17, 1932 2,371,434 Eppler Mar. 13, 1945 2,521,931 Mead Sept. 12, 1950 

